Space catapult startup SpinLaunch comes out of stealth - <AUTHOR> https://techcrunch.com/2018/02/22/spinlaunch/ <comment><USER2> > Two sources say physicists who've looked into the company said a potential > challenge could be air resistance on the cargo when the catapult fires. > Earth's atmosphere is so dense that it could be like the cargo was hitting a > brick wall upon ejection.

Reminds me of the calculation that shows Santa Claus and his reindeer, if they ever existed would have vaporized instantly at the beginning of first Christmas delivery:

...353,000 tons traveling at 650 miles per second creates enormous air resistance — this will heat the reindeer up in the same fashion as spacecraft reentering Earth's atmosphere. The lead pair of reindeer will absorb 14.3 QUINTILLION joules of energy. Per second. Each. In short, they will burst into flame almost instantaneously, exposing the reindeer behind them, and create deafening sonic booms in their wake. The entire reindeer team will be vaporized within 4.26 thousandths of a second. Santa, meanwhile, will be subjected to centrifugal forces 17,500 times greater than gravity. A 250-pound Santa (which seems ludicrously slim) would be pinned to the back of his sleigh by 4,315,015 pounds of force. In conclusion — If Santa ever DID deliver presents on Christmas Eve, he's dead now.

<comment><USER3> Even ignoring air resistance, if your hypothetical spacecraft centrifuge had a radius of one mile, then the spacecraft would still experience 114 g at 3000 miles per hour. If you more realistically spun up Apple's new headquarter with a diameter of 461 meters [1] to one revolution per second, that makes 3240 miles per hour, the spacecraft and the outer wall of your centrifuge would experience a centripetal acceleration of 928 g. Not going to happen. And 3000 miles per hour is also pretty slow, about half the speed in a geostationary orbit, for a low earth orbit you need about 17,500 miles per hour [2] which is almost 6 times faster and would increase the forces 36 times.

[1] [https://en.wikipedia.org/wiki/Apple_Park](https://en.wikipedia.org/wiki/Apple_Park)

[2] [https://en.wikipedia.org/wiki/Orbital_speed](https://en.wikipedia.org/wiki/Orbital_speed)

<comment><USER4> Those orbital numbers are sobering, but there may still be plenty of reason to investigate a launch mechanism where the "fuel" comes from an external source.

I haven't run the numbers, but a quick look at typical delta-V budgets [1] (which calculate atmospheric losses as 1.5 to 2 km/s of delta-v), if one could accelerate something fast enough that it escapes most of Earth's atmosphere (and only then burn for orbital velocity), you'd be saving ~17 to 20% on the delta-v requirements. Due to the nature of the Tsiolkovsky equation, that could be a very substantial saving.

That said, I'm also wondering why a centrifuge would be better than say, some kind of low pressure tube / rail, but I'm sure these guys have done their maths and believe in it.

[1] [https://en.wikipedia.org/wiki/Delta- v_budget](https://en.wikipedia.org/wiki/Delta-v_budget)

<comment><USER5> Scaled Composites tried to solve it by launching from a winged aircraft. (Too bad they seem to have stopped.)

</comment></comment></comment></comment><comment><USER6> The fact that this seems demonstrably impossible on its face, and yet he is raising money, always makes me curious.

During the 'Star Wars' period in the US when the military was going to buy up thousands and thousands of launches to low earth orbit there were probably 1/2 dozen companies pursuing a single stage to orbit (SSTO) type solution. Gary Hudson, the CEO of Rotary Rocket (one of the SSTO companies at the time), gave a great example that showed that because the atmosphere was thick at ground level and thin at altitude you wanted a velocity that proportional to altitude. As he explained it, everything you do to a rocket to reinforce it adds weight, and every pound you add is another 90lbs of fuel (or what ever your mass fraction is). In that way your rocket could be as delicate as a feather if you went very slowly down near the ground and hypersonic near the edge of the atmosphere.

But systems that attempt to impart enough kinetic energy at altitude zero to allow the rocket to coast to orbit require a rocket that is structurally extremely rigid because it withstands both the force of acceleration and the atmospheric drag at its worst. That is astonishingly hard to pull off.

I a serious challenge, first you have to actually start at higher than orbital velocity because you're going to exchange a lot of energy with the air around the air frame. Volcanoes are currently the champions at throwing things up into the air, Mt St. Helens through ash over 100,000 feet up. But if you start your orbit going straight up you won't be able to miss hitting the planet post apogee. The more angled you make your initial shot, the more air you have to go through before you are in space, the more energy you're going to dump in the atmosphere, and the faster you'll have to start.

And all of that makes me really wonder about an engineering solution that fits within all those constraints. What ever it is, it will be super amazing.

<comment><USER7> I wonder if you could sink a very buoyant rocket to the bottom of the ocean with a weight, and then fire up the rocket engine as it breaks through the surface of the ocean with a positive upward velocity.

Presumably drag in water is the biggest issue, which would be somewhat mitigated by the aerodynamic shape of the rocket. I wonder what is the maximum theoretical exit velocity from the ocean, using only buoyancy as propulsion.

<comment><USER7> Related interesting idea: creating a hydraulic catapult to launch the rocket.

[https://www.quora.com/Why-dont-we-launch-spaceships-from- und...](https://www.quora.com/Why-dont-we-launch-spaceships-from- underwater/answer/Bernard-Peek)

</comment></comment></comment><comment><USER8> This reminds me of the "Supergun" that Gerald Bull [2] was trying to build with Saddam Hussein [1].

One of my professors, that worked with Bull at the University of Toronto, told me all about his arms dealing/designing escapades. Bull was ultimately assassinated outside his home in Brussels.

[1] [https://en.wikipedia.org/wiki/Project_Babylon](https://en.wikipedia.org/wiki/Project_Babylon) [2] [https://en.wikipedia.org/wiki/Gerald_Bull](https://en.wikipedia.org/wiki/Gerald_Bull)

<comment><USER9> I heard about Bull in the book Soonish [0], which has a whole chapter on cheap access to space. Readers of this thread might be interested in it.

[0] [https://smbc-comics.com/soonish/](https://smbc-comics.com/soonish/)

</comment></comment><comment><USER10> They mention in the article of being able to launch objects at 3,000 MPH. That's a tad short of the typical 17,500 MPH used for low earth orbit, and that's not counting the extra Delta-V required to resist atmospheric drag.

I'm very glad that this company exists, but this article doesn't help its case very much other than "Hey look, they got a load of funding".

<comment><USER11> Just a wild guess here, maybe they're using a variant of a ramjet, skipping the inefficient speeds, and then propelling it to LEO speed once it's launched.

<comment><USER12> Ramjet would still require atmosphere. If you look at the Japanese SS-520 or the RocketLab's Electron, you don't need a giant rocket to get a small payload to orbit from a standing start. If you give your payload a Mach 5 kick you can eliminate a lot of the propellant mass and get by with smaller rocket motors optimized for high altitude operation.

Elon Musk wants to put 12,000 satellites into orbit. It would be very strange to me if he doesn't have someone looking into the feasibility of a giant subterranean launch tube to do something similar. Get the payload up to Mach 10 on terrestrial power and complete the orbit with a small single stage.

<comment><USER13> > Elon Musk ... giant subterranean launch tube

Hyperloop?

<comment><USER14> The Hyperloop is a rehashed vacuum-train idea originally from the 1800s (reduce air and rolling resistance as the primary forces counteracting speed). [1]

A launch tube would be very different, if for no other reason then the fact that you need to actually jettison the payload at one end at high speed.

1\. [https://en.wikipedia.org/wiki/Vactrain](https://en.wikipedia.org/wiki/Vactrain)

</comment></comment></comment></comment></comment><comment><USER15> I played enough KSP to know that this sort of thing is somewhere halfway up on the list of "things that you might think go to space but don't".

Hitting the atmosphere after accelerating will probably cause most materials outside of reentry heatshield to immediately melt, ignite and explode without particular order of these events. After turning into a molten blob of lava or a spent heatshield, it would still be nowhere close to orbital velocity and would have to fire an engine that somehow survived A) the heat and B) the intense G-forces involved.

I'll probably file this under "solar freaking roadways" and hope they don't try to fire a human in this.

<comment><USER16> Eh, I'm going to give them the benefit of the doubt, mostly because they appear to be able to attract large amounts of VC funding.

When it comes to orbital mechanics, the idea works. You just need to make your starting velocity high enough after it has decelerated though our atmosphere slows down to orbital velocity. Then you just design your ascent capsule to "deal" with the extreme declaration and heating, which isn't a huge problem: Heat shields exist, and so do g-force hardened electronics. Nobody should be under the impression that this will be used to launched anything other than small specially designed g-force hardened satellites.

It's not like "solar freaking roadways" which has blearlying obvious economic and efficiency flaws, the designs for catapult based launchers have been well studied and there is nothing physically stopping them. It's more of a engineering problem.

Honestly, I'm more concerned about the engineering practicalities of building an extremely large centrifuge spinning at some absurdly high RPM (presumably at the top of a mountain, so it bypasses some of our atmosphere)

<comment><USER15> >Eh, I'm going to give them the benefit of the doubt, mostly because they appear to be able to attract large amounts of VC funding.

Just because someone is giving them money doesn't mean they can do it.

>When it comes to orbital mechanics, the idea works.

Of course it does, similar systems have been suggested for lunar transfers to earth (IIRC). Without atmosphere these systems are trivial to implement and use. (Comparatively)

> Heat shields exist, and so do g-force hardened electronics.

Heatshields are rather large and expensive. There is also a difference between heatshields for reentry and heatshields you'd need for leaving the atmosphere efficiently.

At the moment, heatshields are basically ramming through the air and compressing it in front of the aircraft, this is most efficient in reducing velocity and can reduce the temperature at the shield somewhat.

When you fire something through the atmosphere with the goal to get it into a suborbital trajectory you need a different solution; your aircraft becomes a spike/spear, generating friction with air instead of compression. Friction is harder to deal with if I recall correctly from various pages on the topic.

</comment></comment></comment><comment><USER17> Realistically, what is the feasibility of a space catapult? I mean, the speed at ground level to be able to reach orbit must be insanely high, no? This high speed in a thick atmosphere would cause all kind of heating problem on the catapult itself and the "rocket". I wonder what would be the actual numbers.

<comment><USER18> Launch from near the equator, high in the mountains? Chimborazo, Ecuador? At 6000 feet, its half the air pressure of sea level, and 1/4 the atmosphere to travel through. And accessible. A good start?

[https://www.google.com/maps/place/Chimborazo/@-1.4685873,-79...](https://www.google.com/maps/place/Chimborazo/@-1.4685873,-79.014542,11.22z/data=!4m5!3m4!1s0x91d372d7706a480b:0x69d5c66d2e629dff!8m2!3d-1.4693018!4d-78.8169396?hl=en)

<comment><USER19> Going to space is not entirely about being high. It's about going sideways, fast.

And if, at 6,000 feet, air pressure were half that of sea level, nobody would live in Denver and most Tibetans would be dead. Half is more like 6,000 _meters_.

<comment><USER20> Chimborazo is >6000m above sea level tbf and not 6000ft as the OP suggested. It's actually the furthest point from the Earth's centre (the earth's shape gives it a boost over mountains which are higher above sea level but further from the equator)

For related reasons, its difficult-to-reach, low oxygen, snow-covered summit is not ideally suited for building and maintaining a space launch site.

<comment><USER18> "Not ideal" may overlap with 'tremendously cheap' if the SpinLaunch 10-100x cost factor is true. So a few oxygen masks may be worth the trouble. And a highway goes within a few miles of the peak right now.

<comment><USER20> I've been on that highway. Trouble is you're still a few thousand metres of relatively technical climbing or a helicopter ride away from the top. I mean, people can work in some pretty inhospitable conditions if the cost advantages are real, and the payloads you've got to get up there have to be relatively comfortable with being moved to get fired into space anyway, but it's hard to imagine anything on a Cape Carnaveral scale happening there even if Ecuador decides the dollars from supporting space programmes are worth more than the scenery and symbolism

<comment><USER21> I came across the idea of launches from Ecuador while reading about spaeflight. IIRC, I assumed 3,000m launch (assumed a suitable site near Quito exists), and calculated a disappointing, less-than 10% increase in payload, assuming a BFR as the launch vehicle. However, for a kinetic energy launcher, or small rocket like the new record-settinf Japanese SS-520, that improvement would be a lot larger (and more importantly, the logistics a lot easier!).

The thing is, with rocket size increasing, payload increases cubically while air resistance is squared. So for the really big rockets, altitude is not as big of a factor as being near the equator.

If I am not wrong, propulsive landing on drone ships uses another roughly 10% fuel (depends on launch trajectory, etc).

As fossil fuels are non-renewable, and Hydrogen expensive, I am very sure (and even hope to be correct) that in the future we will see launches from high- altitude equatorial regions, using booster-capture technologies and perhaps even terestial-power-assisted launches. Those things may reduce the fuel-cost of escape velocity by 30+%, and when we're sending enough stuff into orbit that this is too advantageous to ignore, we will do it.

But for now, the best way to go is to get really good at building bigger rockets.

</comment></comment></comment></comment></comment></comment></comment><comment><USER22> Could you lift the whole catapult setup to a higher altitude with a greatly reduced atmosphere before firing?

Or create a tunnel ahead of the projectile? You could use a laser to facilitate a artificial lightning strike- and fire the projectile up the thunder-tunnel of the lightning.

</comment><comment><USER23> I assume they are using a cyclotron accelerator.

Basically its a large disk with a spiral track on the inside. The disk is then oscillated in along its flat plane, like this: [https://www.youtube.com/watch?v=OPLzsRojo_A](https://www.youtube.com/watch?v=OPLzsRojo_A)

There was a video of a marble cyclotron, that basically had a spiral like the above, but instead of tilting, the whole disk moved along the z axis (as we look at it, x up, y left and right) it was about 1 meter wide, and was oscillating at about 2hz, that was capable of ejecting marble sized objects at about 500 mph or something similar.

So I can see the method, but I doubt how payloads will survive that level of G.

 _edit_ This idea: [https://www.youtube.com/watch?v=UnZWu1FXxd4](https://www.youtube.com/watch?v=UnZWu1FXxd4)

</comment><comment><USER24> Since we're talking about space, I am wondering when some nation can build a rotating space station.

Null-gravity is nice to play in, and some null-g research is necessary. But to work, and operate normally, null-g sucks. Especially if you need to handle fluids.

And if you need to do an emergency surgery in space, then dealing with floating blood is disgusting and biologically hazardous. As well as dealing with used surgical tools that can float around.

I would rather live in a centrifuge space station, and go to the null-g zone to conduct my work research.

It's interesting how in all scifi movies, all the spacecraft have an artificial gravity.

It's too bad China's proposed space station, will not break new ground, and have a rotating space station. They would need to spend much more money on designing and building it, than what they are willing to spend.

<comment><USER25> You don't actually need a wheel. Just a counterweight and a cable.

It's unlikely a full g is necessary, anyway. A half would do well.

<comment><USER26> You might be able to get by with even less if your goal is to provide a consistent up/down and not have to velcro everything down. I don't have any sourcing for it and obviously it's from a Sci-Fi book, even if it's one that is rather well-researched, but in the Expanse series they use accelerations of around 0.3g a lot (both for stations and ship drives). Would be nice to know if they pulled that number from thin air or what the thought process behind it is.

</comment></comment></comment><comment><USER27> Isn't this obviously impossible?

What sort of launch vehicle or payload is going to tolerate the Gs of being spun at such a high rate. How on earth does this even raise a dollar of funding?

It has crossed my mind in the past why we don't use something like a linear electric motor to help get rockets going off the pad, even just a hundred yards or so of acceleration assist might save a good chunk of fuel. But the rockets aren't exactly designed to have acceleration applied anywhere other than at the engine, so maybe you end up having to add the weight you'd save in fuel back in structure for the ancillary acceleration source.

<comment><USER28> At its face it does sound pretty crazy but I found some analogs of previous and ongoing projects that provide some reason to suspend disbelief.

Here's what I can find on high G launch vehicle's and payloads:

Breakthrough Starshot: Backed by physicist and VC Yuri Milner and lead by former director of NASA Ames, Peter Worden. 10,000 G's. Project Ongoing. [1]

Hiller Hornet: US Army helicopter, powered by jet turbines located at the tips of the helicopter blades. The turbines operated under 14,000 Gs. Project Completed [2]

HARP Project: Joint US Army & Canadian effort. Successfully launched electronics (radios, control systems, etc) and solid fueled rockets. 10,000+ Shock G's. Project Completed. [3]

A variety of documents come up while researching g-hardening electronics. The US Army Research Lab a a few papers. Linked one of them. 30,000 + Shock G's. Various Projects Completed and Ongoing[4]

The Hiller Hornet is likely the most applicable given it is a propulsion system operating at over 10,000 G's. I wonder how they designed the Hornet's turbine given Finite Element Analysis wasn't really a thing in 1950.

[1] [https://en.wikipedia.org/wiki/Breakthrough_Starshot](https://en.wikipedia.org/wiki/Breakthrough_Starshot) [2] [http://www.aviastar.org/helicopters_eng/hiller_hoe-1.php](http://www.aviastar.org/helicopters_eng/hiller_hoe-1.php) [3] [http://www.astronautix.com/a/abriefhistoheharpproject.html](http://www.astronautix.com/a/abriefhistoheharpproject.html) [4] [http://www.arl.army.mil/arlreports/2006/ARL- TR-3705.pdf](http://www.arl.army.mil/arlreports/2006/ARL-TR-3705.pdf)

</comment></comment><comment><USER29> > SEC documents show that Yaney raised $1 million in equity in 2014, the year > SpinLaunch was founded, $2.9 million in equity in 2015, $2.2 million in debt > in mid-2017 and another $2 million in debt in late 2017. Now Yaney confirms > SpinLaunch has raised a total of $10 million to date, and that he's > personally an investor... "The current status of our Series A raise is that > we are still taking meetings with potential investors and have not yet > received an executed offer."

Do I not understand how series of funding works?

</comment><comment><USER30> Which startups are trying to build a launch loop or space towers? I'd love to keep track of those startups.

<comment><USER31> Are you referring to the space tower hypothesized by Thoth Technologies?

[http://thothx.com](http://thothx.com) [https://en.wikipedia.org/wiki/ThothX_Tower](https://en.wikipedia.org/wiki/ThothX_Tower)

</comment></comment><comment><USER32> The child/mythbuster in me wonders what would have if you spun a large disc at this speed and tried to skim it across an ocean

<comment><USER33> probably a lot of smoke and noise, I'd watch it though

</comment></comment><comment><USER34> Dana Andrews used this Spinlaunch idea in his University of Washington Undergraduate Astronautics Capstone Engineering Class to launch Lunar Mining Ores from the moon cheaply. Maybe they intend to use it on the Lunar Poles?

</comment><comment><USER25> What has happened with all the studies about launching to orbit after being dropped from a jet at high altitude?

</comment><comment><USER31> Would it help to catapult the cargo at high altitude where the air is rarefied? That way you have to deal with less atmosphere and the initial energy required for the catapult is smaller. Idk where, maybe the Andes?

</comment><comment><USER35> you could have a covered (hyperloop) train go round and round in the antarctic (against the earth's spin) until in reached escape velocity and segment of the loop would detach and point the train up the space.

A second idea would be to create a bridge from the closest points of africa and south america, use it as a standard bridge between launches, the launches would only have to do 2g to get to escape velocity.

</comment><comment><USER36> I think that this is cool, but I recall reading papers for rail launched vehicles, mostly from the moon, back in the early 80s.

<comment><USER33> from the Moon I can see how it makes sense. From Earth I still have trouble to believe it would work.

That being said I had trouble believing you could land two rocket boosters simultaneously so at worst I'm not surprised, at best it works

</comment></comment><comment><USER37> It's a flywheel, some really good clutch mechanism and a straight track for linear acceleration, right?

</comment><comment><USER38> Is there a calculation to determine a max spin speed of an object? Can an object spin infinitely faster and faster if it had unlimited energy and force spinning it? Is there a name for where centrifugal force is so high that an object rips itself apart? Picturing hand tossing pizza dough as a simple example, but what about massive structures?

<comment><USER39> > Can an object spin infinitely faster and faster if it had unlimited energy > and force spinning it?

Nope. Eventually the centrifugal force exceeds inter-molecular forces.

Not quite what you were asking, but related [https://www.wikiwand.com/en/Roche_limit](https://www.wikiwand.com/en/Roche_limit)

</comment></comment><comment><USER40> The idea of launching objects into space using a catapult interests me if only because my physics profs in high school and university all have at one point or another shot down the idea of space catapults. Since I don't remember exactly what their beef with space catapults was about, I figured I'd have a go and see if I could get an estimation of feasibility myself.

I am also not an aeronautical engineer (or even close to being one), but I do have some free time and I have a notepad.

According to Wiki[1], ∆V to LEO is ~8km/s plus 1.5km/s to account for drag (so a total of 9.5km/s total). The article claims that the craft exits the launch device at ~1.3km/s which leaves 8.2km/s to be accounted for. For the purposes of our math, let us assume that the craft has an alternate way to get up to speed. We'll note that SpinLaunch is not throwing their spacecraft into space at all; in fact, they're barely getting their spacecraft off the ground (relative to LEO).

Even with the significantly reduced launch speed, getting the craft spun up to speed is no small task. The equation for relating linear speed to angular speed is:

       [Linear Speed] = [Rotational Speed]*[Radius]

Since we have a linear speed in mind, we can make assumptions for rotational speed or for the radius of the launching arm and solve for the other. I think revolutions per second is easier to imagine, so we'll just Fermi this out.

If your maximum angular speed is one revolution per second (~6.3rad/s), then your launching arm will need to be ~213m long. To put that in perspective, the centrifuge would need to be about four football fields in diameter. Not only that, but it would be hurling a spacecraft around the circumference once every second! Because the relationship is linear, if you want to halve the angular speed, then you'd have to double the radius. Just building a structure that can not only support the weight of a spacecraft at the tip, have a diameter of 450m, and complete full revolution every second seems like a challenge already.

Additionally, unlike a regular centrifuge, this launch structure would likely not be parallel to the ground either; you want to launch your craft into space after all. Which means that you'll have to deal with unequal forces and accelerations as you spin.

To really put things into perspective, the largest centrifuge in the world is the TsF-18 in Russia and it has a radius of 18m and can only manage 0.65 rotations per second at maximum speed[2].

But hey, I'm no mechanical engineer either, so maybe that's no big deal. Maybe introducing a vacuum in the launch structure makes such a huge difference that getting up to speed is easy enough.

How does one exactly create such a big vacuum chamber though? Even if the height of the chamber is only 5m tall, the total volume is ~710,000m3. The largest vacuum chamber is the Space Power Center and it has a maximum volume of 22,653 m3[3].

You'll need to build something that outspins the largest centrifuge in the world (by more than an order of magnitude) and outsucks the largest vacuum in the world (by more than an order of magnitude). If somehow SpinLaunch can build the most spinniest and suckiest structure ever built, you're still only 13% of the way into space.

Really puts into perspective how outrageous SpinLaunch's claims are.

1: [https://en.wikipedia.org/wiki/Delta- v_budget](https://en.wikipedia.org/wiki/Delta-v_budget)

2: [http://www.rusadventures.com/tour35.shtml](http://www.rusadventures.com/tour35.shtml)

3: [https://www1.grc.nasa.gov/facilities/spf/](https://www1.grc.nasa.gov/facilities/spf/)

<comment><USER28> I have a bit of background on rotor systems. That TsF-18 is puny compared to other rotational systems. See below.

Largest Centrifuge: Regarding the largest centrifuge in the world, perhaps the TsF-18 in Russia has a large diameter but the JET Tokamak [1] flywheel spun a 775 TON rotor at a speed nearly 6 times what is cited for the TsF-18. The Tokamak's centrifuge's provided over 3.8 gigajoules of energy. To provide a more intuitive sense of that energy, 3GJ is equivalent to a 100kg mass traveling at 7.7km/s [2].

Fast Flywheels: OakRidge National Laboratory [3] achieved over a 1.4 km/s tip speed and that was back in 1985.

Large Vacuum Chambers: The Large Hadron Collider[4] is a vacuum system over 5 miles in diameter although toroidal in nature.

1: [https://www.euro-fusion.org/fusion/jet-tech/jets- flywheels/](https://www.euro-fusion.org/fusion/jet-tech/jets-flywheels/) 2: [https://www.calculatorsoup.com/calculators/physics/kinetic.p...](https://www.calculatorsoup.com/calculators/physics/kinetic.php) 3: [http://www.guinnessworldrecords.com/world-records/fastest- ro...](http://www.guinnessworldrecords.com/world-records/fastest-rotating- flywheel/) 4: [https://en.wikipedia.org/wiki/Large_Hadron_Collider](https://en.wikipedia.org/wiki/Large_Hadron_Collider)

<comment><USER40> First off: thanks for the reply. Secondly, how could I forget about the LHC...doh!

So it does seem like it is possible to get a spacecraft spinning up to speed. It'll just require a lot of effort and even more capital.

</comment></comment></comment><comment><USER41> The physics of this makes no sense...

</comment><comment><USER42> I wonder how they plan to reduce the costs of fairings when spaceX fairings cost most than their entire launch cost.

</comment><comment><USER22> So the projectiles are spun, to generate a sort of carvatation effect in atmosphere? Rather brilliant.

</comment><comment><USER43> I'm picturing a daredevil getting shot out of a cannon. Where is super dave when you need him? Could be the spokesperson.</comment>


Please think architecture (2007) - <AUTHOR> https://lists.freebsd.org/pipermail/freebsd-arch/2007-August/006763.html <comment><USER2> Who's right?

Trees couple hierarchy into information, and there lies the problem. Same thing could be modelled as a table, and allow both views:

        root             hw
        vendor_submodule acpi
        vendor           fujitsu
        vendor_feature   lcd_brightness
        submodule        backlight
        feature          brightness
        value            4

Architecture ain't easy...

<comment><USER3> The freebsd laptop I'm writing this on has:

        $ sysctl -a | grep brightness
        hw.acpi.video.lcd0.brightness: 50
        compat.linuxkpi.i915_invert_brightness: 0

So if you want to write a script that works both, you need to put fujitsu- specific knowledge in your script. Vs. alternatively, an interface that works everywhere.

(Incidentally I think this sysctl doesn't do much and I instead use a utility called intel_backlight(1) from ports.)

<comment><USER4> What laptop are you using for freebsd? Also what desktop environment? I've tried forever to get a BSD laptop setup working.

<comment><USER3> Lenovo X1 Carbon 6th gen.

I don't use a big "desktop" like gnome, just a normal/light X setup resembling the 1990s. Lately it's dwm. Sometimes I do others.

Some things that might save you some time in loader.conf:

       acpi_video_load="YES"
       acpi_ibm_load="YES"

Also, had to set ACPI to "Linux" mode in bios. After that plus the two lines above, suspend works.

Also, xf86-video-intel from ports.

Wifi is slow but I'm ok with that.

Long ago I used OpenBSD on a laptop, and in my experience, with thinkpads, it has a bit more of a "just works" feel than FreeBSD for hardware support. But I'm on freebsd because of a few things that don't work on openbsd these days [like linux binary emulation].

</comment></comment></comment></comment><comment><USER5> So what happens if you plug your laptop into a docking station that has its own backlight? What if a new laptop comes out that has multiple backlights (perhaps of different colors)? In both of these circumstances the assumption that there is one backlight is faulty and not future-proofed.

Not to mention that the units don't carry over from one vendor to another.

<comment><AUTHOR> > Not to mention that the units don't carry over from one vendor to another.

Who cares about the units? When was the last time you used a vendor-provided utility to configure a Network Interface Card, instead of just using ifconfig (if you're on BSD)? On OpenBSD, there's also bioctl for RAID management, too — [https://en.wikipedia.org/wiki/Bioctl](https://en.wikipedia.org/wiki/Bioctl). And sysctl hw.sensors for temperature sensors and more.

How's brightness any different? It's a percentage value from 0 to 100%. Would the user really care how many internal settings a given machine has, and that 100% is really just 16 internally?

<comment><USER6> Sure they do! When I press "brightness up" shortcut on my keyboard, I want my laptop to brighten by 1 physical step, or by 2%, whatever is bigger.

Having to press the key multiple times just to get any effect is super frustrating.

<comment><AUTHOR> I think those shortcuts are often handled by the driver itself, so, it'll already know the required stepping. Another option could be to provide such stepping explicitly as another sysctl.

Otherwise, realistically, the keyboard shortcut stepping could simply be assumed to have only 16 variations in the first place, even if you're still using a percentage point through the interface.

</comment></comment></comment></comment><comment><USER7> His next post on that list, on a different subject, is also pretty entertaining:

[https://lists.freebsd.org/pipermail/freebsd- arch/2007-August...](https://lists.freebsd.org/pipermail/freebsd- arch/2007-August/006764.html)

</comment><comment><USER8> Has this changed since 2007? (don't have any freebsd available to check)

<comment><USER9> Guess not: [https://www.freebsd.org/cgi/man.cgi?query=acpi_fujitsu&sekti...](https://www.freebsd.org/cgi/man.cgi?query=acpi_fujitsu&sektion=4&manpath=FreeBSD+12.0-RELEASE)

> hw.acpi.fujitsu.lcd_brightness

From man acpi_fujitsu on an actual system:

      SYSCTL VARIABLES
         These sysctls are currently implemented:

         hw.acpi.fujitsu.lcd_brightness
                 Makes the LCD backlight brighter or dimmer.

         hw.acpi.fujitsu.pointer_enable
                 Enables or disables the internal mouse pointer.

         hw.acpi.fujitsu.volume
                 Controls the speaker volume.

         hw.acpi.fujitsu.mute
                 Mutes the speakers.

</comment></comment><comment><USER10> The "generic" one is necessarily a UI to the device, not the actual device, because there's always some kind of special casing or variation in an abstract property like that. Having the UI is of benefit when it serves as a building block, but not if it cuts off customization for some task.

</comment><comment><USER11> Negative. Backlighting is vendor specific. Different implementations offer different configurations.

I do agree you probably want a base object for inheritance, exposing a common interface wouldn't be a good idea.

No matter what, you need to implement your abstraction. You're always going to end up with a list of vendor specific implementations.

<comment><AUTHOR> > Negative. Backlighting is vendor specific. Different implementations offer > different configurations.

Are you joking? For an analogy, do any NIC vendors even provide their own tools for configuring their Ethernet cards? And even if some do, how many people actually bother to use those, instead of OS-specific utilities like ifconfig? How's backlighting any different here?

<comment><USER12> The networking analogy would be things like DPDK, where yes, you do need to know what the hardware is doing, and yes, there's vendor-specific support. The answer to "how many people bother" would be "as many as have a damn good reason to do so." [http://doc.dpdk.org/guides/nics/overview.html](http://doc.dpdk.org/guides/nics/overview.html) shows the non-homogeneity of NIC feature support across vendors; if you don't care about this stuff, there's no reason to know it, but if you do, it's make or break.

<comment><AUTHOR> Sure, that's a lot of variation. Sure, some of these features are essential for certain applications, like checksum offload etc. However, most of these features are still uniform enough that a whole bunch of them are supported by standard drivers included with all BSD operating systems, and configurable with the standard ifconfig of each BSD, too:

[http://mdoc.su/-/ifconfig.8](http://mdoc.su/-/ifconfig.8)

The fact that you even have a whole table with these features shows that these features are not that difficult to categorise and unbrand to be general enough to have OS-defined behaviours and configurations for.</comment></comment></comment></comment>


Solution to Deflation: Abolish Cash - <AUTHOR> http://business.timesonline.co.uk/tol/business/economics/article6531299.ece

<comment><USER2> Price deflation is the normal state of affairs when the Government isn't inflating the currency. It isn't a problem to be solved. A financial bubble is the problem. Japan is trying to create a bubble in its economy. Even if they succeed it will deflate at some point in the future. The bigger the bubble, the deeper and longer the recession/depression that follows the bubble.

<comment><USER3> Deflation may be the "normal state of affairs when the Government isn't inflating the currency", but that doesn't mean it isn't a problem. And that's a flawed description of affairs.

Deflation is more specifically the normal state of affairs when the government enforces a legal tender law on a scarce, slow-growing currency such as gold. It doesn't happen when the currency is fast-growing, like silver was in the late 19th century, or like tobacco was during the colonial period. And it doesn't happen in a barter system. The establishment of the gold standard was a major political effort that was only accomplished by the McKinley administration around the turn of the 20th century (having been preceded with an even less tenable system of bimetallism that finally collapsed due to the Nevada silver rush).

As for whether deflation is a problem, deflation disincents both investment and spending, which means in a very real way that deflation disincents economic growth. The situation you describe would also be possible only with a return to the gold standard, which would effectively price gold out of any kind of industrial use--something that would have negative economic repercussions in itself, and which would likely cause extremely high rates of deflation in the future.

<comment><USER2> I should have said "mild deflation":

<http://www.cato.org/pubs/policy_report/v21n3/cpr-21n3.html>

<comment><USER3> Mild deflation is better than runaway deflation just as mild inflation is better than runaway inflation. But it seems that mild inflation is actually better than mild deflation.

I'm not impressed by think tanks: they come up with the conclusion first and the reasoning second.

</comment></comment></comment></comment><comment><USER4> > _Solution to Deflation: Abolish Cash... Without physical cash, a central > bank can set rates exactly where it likes, runs the argument._

Solution to Everything: introduce an Orwellian total control scheme. I like my anonymous money just fine, thank you.

<comment><USER5> So right, and let's not forget that EVERY electronic transaction incurs a cost.

To paraphrase, "I for one, welcome our future Visa overlords."

<comment><USER6> You have to admit it's a brilliant business model. "Let's just go and take a cut of every money transaction anyone, anywhere ever makes". Bulletproof.

<comment><USER7> That's how a VAT is supposed to work. In theory it is the most efficient and fair form of taxation.

I think Japan could maybe pull it off, but I wouldn't be too surprised if it bit them hard in unexpected ways.

<comment><USER5> No more panhandlers.

</comment></comment></comment></comment></comment><comment><USER8> I suspect the article is confusing cash and cash equivalents like savings accounts. It says that cash is 16% of the Japanese GDP. I have a hard time believing that. The Japanese have a high savings rate and the predominant means of saving is postal (government) savings accounts. (The last time I read about it was the middle of the last decade.) If I am correct, they are contemplating negative interests rates on savings accounts. They might be considering the elimination of cash to prevent people from pulling cash out of their savings accounts and putting it in their mattresses or lock boxes.

</comment><comment><USER9> If any country can pull it off, Japan can. The economy is dominated by a relatively small number of large conglomerates.

It would be much harder to pull it off in more fragmented economies (except for very small ones perhaps).

</comment><comment><USER10> I'm assuming that negative interest rates would encourage spending, but I'm wondering why this wouldn't simply encourage people to move their money to foreign banks?</comment>


Cloudflare CTO: "If we did [take on GitHub] what features would you like?" - <AUTHOR> https://twitter.com/jgrahamc/status/1134092076382064640 <comment><USER2> I'm amused this is here. This was a random reply to someone who thought maybe we were doing this. To be clear: that's all this is.

But I'm happy to hear all the suggestions.

<comment><USER3> Too bad, I was really excited about Gitflare :)

<comment><USER4> Cloudgit has more buzzword power.

<comment><USER5> If we smash them together we'd get Gitgit, which is probably the best option.

<comment><USER6> I need a name for our internal Gitea instance, do you mind if I grab this idea? Haha.

* gitgit.at — as in, gitgit.at/username/ * gitgit.dev * gitgit.ist — sounds funny

<comment><USER6> Thank you! Registered .dev =)

</comment></comment></comment></comment></comment></comment><comment><USER7> Cloudflare folks. Please don't do this. I don't know if Mr.Cumming is serious.

As a user of CF, I hope you folks go a lot deeper than broader. Example: Better cache management – compete with Fastly, my tickets on load balancer bugs were open for almost 6 months, etc.

<comment><USER8> Another example: unify all the separate "rule" types. There's page rules, firewall rules, IP access rules, user agent rules, etc. It can get unwieldy.

<comment><USER2> Agreed.

</comment></comment></comment><comment><USER9> The amount of business Cloudflare employees handle direct over Twitter, and the amount of responsiveness from their higher-ups on it is... kinda incredible. I imagine it's only practical because Cloudflare doesn't have a lot of _public_ brand awareness beyond tech folks.

<comment><USER2> We care a lot about the product and the people who use it.

<comment><USER10> If only you could say the same about potential employees. Your recruiters seem to have a penchant for completely ghosting candidates, even when several interviews deep into the interview process. This has happened to me twice now, with two different recruiters, even after being told by the interviewers that I was well qualified and surely would be moving to the next step. And after glancing at Glassdoor reviews, this doesn't seem to be uncommon whatsoever.

<comment><USER2> If you are willing please email me so I can look into this.

</comment></comment></comment></comment><comment><USER11> I'd like Cloudflare to not do a Google and let a thousand flowers bloom only to let most of them wither. They seem to be taking on a lot just with their new public VPN service.

<comment><USER12> still 170K on the waitlist after 2 months? haha

<comment><USER2> soonhorse.jpg

<comment><USER13> I didn't understand the reference, so I googled the reference and this comment is already trending #1 on Google.

[https://www.google.com/search?hl=en&q=soonhorse.jpg](https://www.google.com/search?hl=en&q=soonhorse.jpg)

Online marketing at it's best.

I'm surprised I've not seen this meme before. [https://soon.horse/](https://soon.horse/)

</comment></comment></comment></comment><comment><USER14> One feature I would love is a global code search that has the quality of the repo (as measured by forks/stars/pagerank...) as a part of relevance ranking. A use case is simple: I have some library and I am not exactly sure how to use it, so I go into global code search and try to find usages of that method. First thing that comes would be some relevant code in a big context of a well engineered repository.

<comment><USER15> > quality of the repo (as measured by forks/stars/pagerank...)

These two seem unrelated. Quality is not measured by popularity. There is plenty of popular stuff that's junk, and good stuff that nobody uses.

<comment><USER16> Precisely. For my organization, I'm looking for a way to quantitatively measure and compare quality/security postures of repos/packages when importing.

<comment><USER15> Sounds tough. What are your ideas to measure so far?

For the security angle it seems the first naive thing would be to count prior known vulnerabilities, but then, the projects that do absolute worst at that are not going to have _discovered_ their security bugs let alone document them well.

</comment></comment></comment></comment><comment><USER17> Decentralized SCM features for issues, CI, etc. GitLab is great but it is still mostly centralized. Creating a modern connector for IPFS would be awesome.

</comment><comment><USER18> cloudflare running SMTP relays for your own mail system, in both directions, doing spam filtering, etc, could be valuable. argo, edge workers, etc could all be useful in an email environment.

most everyone is already convinced you can't run a mail server yourself, so perhaps the haters wouldn't think that cloudflare is ruining anything by getting involved in mail?

</comment><comment><USER19> The most useful thing Cloudflare could do is allow us to disable the `__cfduid` cookie. That's one of the big reasons I stopped using Cloudflare on a public-facing API/CDN.

<comment><USER20> Just curious, what is your concern? Is it privacy related? Or does it inhibit consumption of APIs you tried to host with them? I don't like the header either and I have a public API with Cloudflare but it hasn't caused any technical issues as far as I know.

</comment></comment><comment><USER21> The only non-core-business work that I really want from Cloudflare is to do something with LuaJIT stewardship, because I thought they were supposed to be taking the helm and the official GitHub repo is basically completely dead.

</comment><comment><USER2> More seriously. I'd be curious to hear about what you'd build on our network. We are all over the world and it would be fun to hear about companies other than GitHub that you think we should disrupt.

<comment><USER22> I'm a big supporter of Cloudflare and have been using it for almost 8 years. I personally don't think doing something like that is what Cloudflare needs.

What Cloudflare needs is further customization, especially in regards to caching. We actually had to migrate a certain part of our infrastructure to Fastly due to the lack of caching customization/rules.

I'd like to see:

\- Custom caching rules similar to the new firewall rules

\- Finer granularity of the cache expiry (I'm aware Enterprise has the ability to cache for 30 seconds, but we don't want to upgrade to Enterprise just for that one thing).

\- Cache hit rate analytics grouped by path/domain/etc

<comment><USER23> FWIW, our Workers product is pretty good at allowing you to define custom caching rules. We have a section in the Workers docs specifically focused on the Cache API: [https://developers.cloudflare.com/workers/reference/cache- ap...](https://developers.cloudflare.com/workers/reference/cache-api)

If that doesn't help you build what you're looking for, happy to chat via email and hear more about what you need: kristian@cloudflare

<comment><USER24> I've submitted suggestions to some people but I believe with the workers it should be possible to create your own custom pull/push CDN because of the granularity controls they have added. It used to not be possible to interact with the caching layer but since they have added controls for that (about a year or so ago)

Also your link is missing a trailing slash (which is odd that their router doesn't add that). [https://developers.cloudflare.com/workers/reference/cache- ap...](https://developers.cloudflare.com/workers/reference/cache-api/)

</comment></comment></comment></comment><comment><USER25> Are there any updates to the Cloudflare Registrar?

Would be awesome to have marketplace or master/sub accounts. That is, launch a saas say a landing page builder and then allow my customers to also purchase domains from my saas (under my brand account) and have them automagikally configured. Instead of having the user to use namecheap/godaddy and mess around with their crappy control panel. Maybe have an opportunity to raise the price by a $1 [to the end user] and have revenue stream?

<comment><USER26> We do have a product called SSL for SaaS which handles most of the components of that flow like DNS and TLS certificates. The actual domain registration will take a bit longer to integrate, but I'm guessing you could make it work using our API.

</comment></comment><comment><USER27> A couple CF items I'd like:

1) Vary by cookie for $20/mo or free plans

2) A page rule for "don't send origin cookies" or something (useful for not passing through those headers from the origin for assets/etc)

3) getting the peering connections better in AU so the network handles traffic like normal instead of only $200/mo plans getting priority/local AU routing

</comment><comment><USER28> If Cloudflare wants to branch out, here're an idea.

Global Memcached or Redis. Support caches near the edges. SPA or apps running on a client's browser/machine can use the one nearby. Support pre- populating/warm-up the caches in batch.

<comment><USER29> CF already supports this type of thing, workers and the kv store ...

[https://www.cloudflare.com/products/workers- kv/](https://www.cloudflare.com/products/workers-kv/)

<comment><USER30> Workers-KentonVarda? Kidding of course but wouldn't be surprised if he's working on that product... :)

</comment></comment></comment><comment><USER31> I'd rather they took on Jira.

</comment><comment><USER32> Permanent presence in China.

</comment><comment><USER33> How about Github without a big corporation? Not controlled by Cloudflare, ddecentralized and uncensorable. Like bittorrent, but for git repos, issues, etc.

<comment><USER34> So... git? It's already designed to be decentralized.

Hosting a public read-only repo would be as easy as standing up NGINX and pointing it at your repo folder, afaik.

At my previous job, we all had individual dev machines that we each had accounts on. So, we each had a copy of our repos that we could push to/work from. I wrote a little git alias that would add remotes for each others' machines so we could pull directly from each other (though we couldn't push).

Hell, even a "private" git repo wouldn't be too hard as long as you don't care about per-project permissions. Just make a user (e.g. 'git') that has read/write access to the folder and add some SSH keys to authorized_keys. Shazam, you have a private, self-hosted git repo at ssh://email@example.com:path/to/repo.git.

<comment><USER35> Bare git only stores code, not issues, tickets, wiki, and all the stuff that goes beyond source files. There are a myriad of open source solutions for this, but there is no standard format that allows easy migration and inter- linking.

<comment><USER36> Well for wiki, usually a branch containing markdown will transfer well across forges. Issues and PRs are the real issue. I've been hoping git appraise would get supported by the forges for distributed PRs, but it doesn't look like that'll happen.

Gitlab is implementing MRs via git send-email though, which is part of an epic to federate Merge Requests: [https://gitlab.com/groups/gitlab- org/-/epics/260](https://gitlab.com/groups/gitlab-org/-/epics/260) .

<comment><USER35> Very interesting that gitlab is standardizing on the de facto standard of patch requests! How ironic it is that the existing git-request-pull isn't used more than needed thouh

</comment></comment></comment></comment></comment><comment><USER37> Please no, as a TOR user f*ck Cloudflare.</comment>


Byte magazine archives - <AUTHOR> http://archive.org/details/byte-magazine <comment><USER2> This letter from Bill gates is priceless: [http://ia701209.us.archive.org/BookReader/BookReaderImages.p...](http://ia701209.us.archive.org/BookReader/BookReaderImages.php?zip=/32/items/byte- magazine-1975-11/1975_11_BYTE_00-03_Is_This_Next_jp2.zip&file=1975_11_BYTE_00-03_Is_This_Next_jp2/1975_11_BYTE_00-03_Is_This_Next_0087.jp2&scale=2.5842607313195547&rotate=0)

</comment><comment><USER3> Archive.org has a lot of collections of periodicals, and there's a lot of interesting stuff in there, especially stuff relating to computer history. They've got the full archives of the old Computer Chronicles TV show on there as well.

But their UI for browsing these collections is unusable. I haven't been able to find any way of exploring these collections chronologically, or searching within the content ofa specific collection or issue and sorting/filtering the results to identify what I'm looking for.

Compare this to the way Google organizes similar collections: here's their archive of InfoWorld, going back to 1975: [http://books.google.com/books?id=tDcEAAAAMBAJ](http://books.google.com/books?id=tDcEAAAAMBAJ)

</comment><comment><USER4> Ah, so many memories.

How Text Adventures Work! [http://archive.org/stream/byte- magazine-1980-12/1980_12_BYTE...](http://archive.org/stream/byte- magazine-1980-12/1980_12_BYTE_05-12_Adventure#page/n159/mode/2up)

What is FORTH? [http://archive.org/stream/byte- magazine-1980-08/1980_08_BYTE...](http://archive.org/stream/byte- magazine-1980-08/1980_08_BYTE_05-08_The_Forth_Language#page/n101/mode/2up)

The Coinless Arcade! [http://archive.org/stream/byte- magazine-1981-12/1981_12_BYTE...](http://archive.org/stream/byte- magazine-1981-12/1981_12_BYTE_06-12_Computer_Games#page/n37/mode/2up)

</comment><comment><USER5> There is also a torrent ( [http://thepiratebay.sx/torrent/7978965/](http://thepiratebay.sx/torrent/7978965/) ) which has the ones at archive.org and more, with some replaced with higher quality scans. And ftp://helpedia.com/pub/archive/temp/Byte/ has some that aren't in either the torrent or archive.org yet.

[http://atariage.com/forums/topic/167235-byte- magazine/](http://atariage.com/forums/topic/167235-byte-magazine/) is where people doing the scanning are/were hanging out. Scanning seems to have kinda stalled recently. :(

<comment><USER6> It seems some of the higher quality scans can be found here on archive.org: [http://archive.org/details/byte-magazine- rescans](http://archive.org/details/byte-magazine-rescans)

</comment></comment><comment><USER7> I remember reading Jerry Pournelle "Chaos Manor" every month, as a 14 year old. English is not my first language and I'm sure reading Byte has taught me a lot of English. Fond memories.

<comment><USER8> Oh, the memories indeed...:

[http://www.jerrypournelle.com/archives2/archives2mail/mail84...](http://www.jerrypournelle.com/archives2/archives2mail/mail84.html#Wednesday)

</comment></comment><comment><USER9> This is brilliant, thanks for linking this up.

Here is the famous Smalltalk issue Aug 1981. [http://archive.org/details/byte- magazine-1981-08](http://archive.org/details/byte-magazine-1981-08)

</comment><comment><USER10> Cool. Here's the fall 1979 Lisp issue: [http://archive.org/details/byte- magazine-1979-08](http://archive.org/details/byte-magazine-1979-08)

</comment><comment><USER11> In the early 80's, my mom got a subscription to Byte, and I eagerly awaited every issue. My drug of choice was "Ciarcia's Circuit Cellar," which forged a connection for me, between my nascent interests in electronics and programming.

</comment><comment><USER12> Hooray!

But this isn't going to stop me from taking 200 pounds of physical Byte with me to every new home I move.

<comment><USER5> Good! How about scanning in some of the still missing issues? ;)

<comment><USER12> I'd be happy to, if someone can hook me up with a scanner that can do the job at a reasonable speed. I'm in the Seattle area and can bring them where ever.

My set is far from complete but we can all put our sets together.

</comment></comment></comment><comment><AUTHOR> And let's not forget early cats on the Inter... well, cats. [http://i.imgur.com/1XsRylm.png](http://i.imgur.com/1XsRylm.png)

</comment><comment><USER13> Now, where's the UnixWorld archive?</comment>


Is Twitter causally-consistent? - <AUTHOR> https://muratbuffalo.blogspot.com/2018/11/is-twitter-causally-consistent.html <comment><USER2> Isn't this a known feature of Twitter, usually called a soft block or forced unfollow? You block and unblock someone quickly and it forces them to unfollow you (and more importantly, does not signal them that it happened). I have heard of people fearing harassment to use this technique to get themselves out of a person's timeline (out of sight, out of mind) without the pseudo- confrontation of a block.

<comment><USER3> Isn't it weird that someone else controls this. It seems like a website removing itself from your bookmarks.

Maybe twitter could instead work on not being a terrible way to communicate coherent thoughts to each other instead.

<comment><USER4> I would argue that it is closer to being unfriended on Facebook than a website removing itself from your bookmarks.

<comment><USER3> Facebook is mostly info that is scoped to a defined set of people. It makes implicit sense to have your access to private information removed if you no longer qualify eg no longer a friend.

Twitter is publishing data that is world visible and making it hard for individuals who have been snubbed to keep track of what everyone including them if they log out can in fact see by removing their bookmark to same.

The behavior of toggling block is weirder yet because the data is world published, you can read it, you can follow it but someone else has reached out and toggled the state of your account in some weird spooky action at a distance fashion that works only because it confuses people.

Well designed things work in a way that is predictable to users. Who would predict that your follow status on accounts would from the perspective of the user toggle itself randomly.

It's even worse that twitter sees purpose built for short toxic exchanges too short and badly organized for anyone to get each others point where the standard protocol is to disengage from anyone who disagrees and shout at all the people who believe exactly as you do.

</comment></comment></comment></comment><comment><USER5> I find designing for different consistency (trade offs with scale etc.) models super interesting. Where can I find work like this ? I am assuming at big companies this work is already done. Any distributed systems experts here that can point me to some companies and / or small projects I ca build on the side.

<comment><USER6> Martin Kleppmann's book Designing Data-Intensive Applications has two chapters where it talks about consistency (one about replication and another one about consensus and consistency). That books reference sections for each character are goldmines.

The work is never "completely done" because most of the known or reliable solutions involve choosing tradeoffs with scalability, speed or data locality, so you can always go bespoke to optimize for the current business needs, and when they change you may need to change protocols or algorithms again.

</comment></comment><comment><USER7> Could someone explain casual consistency to me? Is it just about not showing earlier messages to someone who got blocked, or is there something more to it?

<comment><USER8> Why call it causal though? It seems like temporal consistency to me. What's the causation aspect?

<comment><USER9> because the thing that needs to be maintained is the causal ordering of events. For the example from TFA, block -> tweet and tweet -> block have the causal effect of the blocked user seeing or not seeing the tweet respectively. Phrasing it as causal ordering removes time from the equation, which you aren't always able to take into account with distributed systems. Causal ordering also allows for causally unrelated events to appear in any order, for example updating your bio and posting a tweet. Check out the wiki article on logical clocks for a rough starting point in delving into this topic: [https://en.wikipedia.org/wiki/Logical_clock](https://en.wikipedia.org/wiki/Logical_clock).

<comment><USER10> A more common example of causally unrelated events is two people tweeting from different parts of the world that don't follow each other. The order these appear somewhere really doesn't matter to anyone.</comment></comment></comment></comment>


HTML5 for total Beginners - <AUTHOR> http://www.html-5-tutorial.com/

<comment><USER2> This is really poorly written, and the author seems to even admit he/she is confused about certain parts of HTML5. The site is basically an intro into a handful of new HTML elements, without any mention of new APIs in HTML5 like Canvas, Microdata, Audio/Video, various Storage engines, etc. Sites like this just confuse those already "green" in the world of HTML5.

Oh, also, on the "All HTML Tags", the author links directly to w3schools.com pages. Lest we forget: <http://w3fools.com>

</comment><comment><USER3> Well laid out! Perfect for a friend...

<comment><USER4> I disagree. The layout seems really tight, and hard to separate content from navigation and advertisements.

In my opinion the ads and donate button make this site feel insincere and possibly even spammy. What is the author's motivation? To make a positive influence and educate, or to gain traffic and make a profit?

There are already trust issues that many people have with w3schools. If I wanted to use this site as a reference or recommend it to others I'd like to have the confidence that quality, accuracy, and reputation are the highest priority. If the author is going to try to monetize this site, great! I just think it would be a lot more effective to tastefully tweak the layout to make a cleaner distinction between content, advertisements, and navigation.</comment></comment>


The Lost Civilization of Dial-Up Bulletin Board Systems - <AUTHOR> http://www.theatlantic.com/technology/archive/2016/11/the-lost-civilization-of-dial-up-bulletin-board-systems/506465/?single_page=true <comment><USER2> I still remember the BBS days quite fondly. They're one of those things that you talk about in that "Ahh, the good old days" way.

My first computer after returning to the United States was an Apple Performa 467, and a Global Village 2400 baud modem. I found the legendary Mac app Zterm to dial into some local BBSs in the Sacramento area and then again when I moved to Seattle. I spent more hours playing Galactic Empire (I liked the Major BBS) than I can even remember. The thing I loved about the BBS community (at least in my experience) was that it was usually local, and unless they told you who they were, you didn't care (or know) who was behind the screen name. They were just another user that you chatted with about whatever was going on. People were using the Teleconference feature and it was a common thing to find that all of the lines were used by people logged into Tele. Sometimes there was that one user in MajorMud or Kyrandia or something but most people were in tele. Then someone would say "Coffee in 10" and that was the queue to disconnect, hop in the car, and drive over to Java City at 18th & Capital.

Good times. Met some people in the BSB scene that I'm still friends with, 20 years later.

</comment><comment><USER3> This article brings back some memories of pre-Internet days. 12 years old with an NEC PC-9801, dialing up a local BBS of techies and motorcycle enthusiasts. This led to getting deep into a BBS written in Pascal, called WWIV, printing out the code (as thick as a book) and porting it to Japanese. My goodness, I just found that the project still exists! ([http://www.wwivbbs.org/](http://www.wwivbbs.org/))

"Lost civilization" is a nice metaphor, there is certainly an archaeological aspect to these surviving artifacts.</comment>


Examining overlooked clues reveals how ultrasound could have caused harm in Cuba - <AUTHOR> https://spectrum.ieee.org/semiconductors/devices/how-we-reverse-engineered-the-cuban-sonic-weapon-attack <comment><USER2> 1\. They cannot claim they discovered constructive/destructive intereference

2\. They cannot claim they discovered interference that shifts frequency.

3\. They cannot claim to have "Reverse engineered the Cuban "Sonic Weapon" attack"

They instead PROPOSE the U.S. Embassy in Cuba has brain-altering levels of noise in the ultrasonic region somehow caused by two or more simple,low level and possibly common ultrasonic emitters without malicious intent and THAT'S why some people can hear it...

Xu's other recent works has been lacking meat and are better at fear-mongering (Tesla ultrasonic 'hack', Smart grid 'hack').

Xu's ultrasonic Tesla 'hack' showed how dangerous the pedestrian avoidance system was by wrapping one of her graduate students in Michelin Man-sized ultrasonic dampening material. Tesla had to make an uncharacteristically brusque comment stating they couldn't reproduce anything of risk to Tesla drivers in the world.

She is the equivalent of the National Enquirer in the security research world and steadily increased her ability to clickbait.

</comment><comment><USER3> Couldn't they obtain a 7khz tone by mixing any two tones seperated by 7khz and applying a low-pass filter? I don't see how this proves anything.

And the 155dB number cited by the Canadian government would require considerable (hundreds of watts) of power to produce at close range.

This whole case defies logic. The early reports were of mysterious symptoms not associated with any obvious exposure. Once ultrasound/infrasound began being mentioned, people began reporting hearing mysterious sounds.

The recording makes even less sense: If the sound levels were really sufficient to cause physical trauma, surely they would overwhelm the phone's microphone?

<comment><USER4> > Couldn't they obtain a 7khz tone by mixing any two tones seperated by 7khz > and applying a low-pass filter?

I don't understand this comment. Are you implying that a low-pass filter would shift the frequencies of part of the signal rather than (mostly) filtering some of the frequencies away...?

<comment><USER5> [https://en.m.wikipedia.org/wiki/Heterodyne#Mixer](https://en.m.wikipedia.org/wiki/Heterodyne#Mixer)

> In the most common application, two signals at frequencies f1 and f2 are > mixed, creating two new signals, one at the sum f1 + f2 of the two > frequencies, and the other at the difference f1 − f2.

Then the low pass filter is used to remove the original signals and the sum, leaving only the difference.

</comment></comment></comment><comment><USER6> An earlier version of this work was discussed at [https://news.ycombinator.com/item?id=16515552](https://news.ycombinator.com/item?id=16515552).

Since commenters here are objecting to the article title as misleading, we've replaced it with the subtitle (with s/Havana/Cuba/ to fit in 80 chars).

<comment><USER2> Not you nor submitters fault. The ire of the intelligent community is towards the people behind the obvious click-bait paper and article.

</comment></comment><comment><USER7> The other attack they described ("DolphinAttack") is intriguing. I've yet to read the paper (but plan to), but the idea of Voice control being ever more present and likely extending to control of more parts of our lives (Banking, Vehicle Controls, Home Security...) could make this a pretty effective attack vector.

<comment><USER8> > could make this a pretty effective attack vector.

Until we start putting high order low pass filters in everything.

</comment></comment><comment><USER9> What a weird, rambling article. I read the whole thing and I'm really not sure what point they were trying to make. Two ultrasonic signals can interfere to produce lower wavelength sound? That's kind of obvious to anyone who has studied signals...

<comment><USER10> I agree it was poorly written.

I believe the intent was to say:

A) We have recording from Cuba, therefore there's proof of ultrasonic noise.

B) This noise we have is in the audible spectrum, but we have reason to suspect it's from the interaction of two ultrasonic frequencies that together produce a very whiney audible frequency

C) Ultrasonic noise can be used for spying and voice-injection, so there's a potential motive for the US to use such technology at an embassy.

</comment></comment><comment><USER11> Just a brief question from a non-engineer: Is this the same kind of phenomenon that produces the illusion of a fifth voice in a barber shop quartet? Thanks!

</comment><comment><USER12> A much better source... [https://www.scientificamerican.com/article/ldquo- sonic-weapo...](https://www.scientificamerican.com/article/ldquo-sonic-weapon- attacks-rdquo-on-u-s-embassy-don-rsquo-t-add-up-mdash-for-anyone/)

</comment><comment><USER13> This is the last movement of Jean Sibelius Symphony No 1 in E minor: [https://www.youtube.com/watch?v=dCIw_4oJ4Gg&t=27m20s](https://www.youtube.com/watch?v=dCIw_4oJ4Gg&t=27m20s)

At about 36m you can hear the rumbling IMD effects.

</comment><comment><USER14> > Xu's 2017 paper "DolphinAttack: Inaudible Voice Commands" describes how we > used ultrasonic signals to inject inaudible voice commands into speech > recognition systems such as Siri, Google Now, Samsung S Voice, Huawei > HiVoice, Cortana, Alexa, and the navigation system of an Audi automobile.

So cool. I had this idea a long time ago but never approached it. Kudos to them for some follow through.

</comment><comment><USER15> Until and unless they actually test their "reverse-engineered" device with live subjects under similar conditions to what has been reported in Cuba, how valid is that claim?

Edit: this is, of course, a rhetorical question. The "reverse-engineered weapon" claim is clearly false.

<comment><USER16> They make this point themselves in the article: they can account for the unusual recording from Cuba, but not for people's symptoms.

>> While the math leads us to believe that intermodulation distortion is a likely culprit in the Cuban case, we haven't ruled out other null hypotheses that may account for the discomfort that diplomats felt. For example, maybe the tones people heard didn't cause their symptoms but were just another symptom, a clue to the real cause.

<comment><USER17> > While the math leads us to believe that intermodulation distortion is a > likely culprit in the Cuban case, we haven't ruled out other null hypotheses > that may account for the discomfort that diplomats felt. For example, maybe > the tones people heard didn't cause their symptoms but were just another > symptom, a clue to the real cause.

Unless what I read was just plain lies, I don't see how this is plausible. Just reading The Guardian's article [1] I see no room for other plausible explanations in every case... remember there were _at least 21 US victims_ (!!):

 _The blaring, grinding noise jolted the American diplomat from his bed in a Havana hotel. He moved just a few feet, and there was silence. He climbed back into bed. Inexplicably, the agonizing sound hit him again. It was as if he'd walked through some invisible wall cutting straight through his room._

 _Soon came the hearing loss, and the speech problems, symptoms both similar and altogether different from others among at least 21 US victims in an astonishing international mystery still unfolding in Cuba. The top US diplomat has called them "health attacks"._

 _New details learned by the Associated Press indicate at least some of the incidents were confined to specific rooms or even parts of rooms with laser- like specificity, baffling US officials who say the facts and the physics don't add up._

[1] [https://www.theguardian.com/world/2017/sep/14/mystery-of- son...](https://www.theguardian.com/world/2017/sep/14/mystery-of-sonic-weapon- attacks-at-us-embassy-in-cuba-deepens)

<comment><USER18> Sounds a lot like some sort of constructive interference. Or highly directional microwaves of course.

<comment><USER17> Microwaves carry sound now?

<comment><USER18> Modulated microwaves could. There are reports of random metal items suddenly playing local high-powered radio stations, and modulated/pulsed microwaves can cause [https://en.wikipedia.org/wiki/Microwave_auditory_effect](https://en.wikipedia.org/wiki/Microwave_auditory_effect)

Note that the purpose of the microwaves doesn't have to be frying someone's brain or creating sound; it can be some unrelated attempt to e.g. try to intercept data think about possible attempts to use preexisting materials in a way similar to [https://en.wikipedia.org/wiki/The_Thing_(listening_device)](https://en.wikipedia.org/wiki/The_Thing_\(listening_device\))</comment></comment></comment></comment></comment></comment>


Angular application bundles using Rollup, Webpack and the Closure compiler - <AUTHOR> http://www.syntaxsuccess.com/viewarticle/angular-application-bundles <comment><USER3> I've long felt that the front end community could benefit from making heavier use of the Closure Compiler. It has been very good for a very long time now.

The downside to its age is that it likes to do things its own way; it's had a static module system since _long_ before ES2015 modules or even CommonJS modules existed. It does have support for other module systems now, though. And as the article mentions, it performs optimizations far beyond what other JS tools do.

One of the big things people disliked about the compiler is that to get maximum optimizations out of it, you had to write your JS in a relatively static way, preferably with JSDoc type annotations.

This is less of a barrier now, I think; TypeScript has become quite popular in the front end community, and the Angular team has created TSickle[1], which allows the TypeScript compiler to output Closure annotated JS.

Webpack is a lot more capable, but also results in shipping a much larger code bundle to your users. This might not matter so much for desktop clients, but in many parts of the world, mobile users still have pretty restrictive data caps, and overages are very expensive.

[1][https://github.com/angular/tsickle](https://github.com/angular/tsickle)

</comment><comment><USER4> The Closure ecosystem definitely evolved a bit differently from the rest of the JS world, but it pioneered some techniques 10 years ago that the rest of the community is only now rediscovering, like isomorphic rendering and type checking. Soon we'll probably see something that minimizes CSS (I'm joking - I'm sure there's a webpack plugin, but I'd be surprised if it were as high quality).

It's an interesting case study in why developer UX is so important - <USER2> never really "fit in" with other tools, which I think really hurt its adoption.

</comment><comment><USER5> I'd also recommend people interested in the Google Closure Library to try out ClojureScript. All ClojureScript code and libraries are automatically compatible with Google's Closure compiler advanced compilation.

It supports working with JavaScript libraries who are also compatible, or at the sacrifice of less optimizations, it lets you work with non compatible JavaScript libraries also.

For example for Angular, you just need to specify an extern file. It will still optimize parts of it, but it won't do symbol renaming. (Disclaimer, I've never actually tried to use Angular with CLJS, but I believe this is true)

For libraries which are completly non compatible, you can import them as foreign libraries and they'll just bypass the advanced compilation, but all your CLJS code and everything else which can be optimized will.

Here's a template to get you started with Angular2 and CLJS [https://github.com/steveshogren/angular2-cljs](https://github.com/steveshogren/angular2-cljs)

</comment><comment><AUTHOR> Hi. The author of the article here.

The webpack and Rollup experiments were done with uglify and gzip enabled. The numbers are based on the reported values in Chrome when running the code here: [http://www.syntaxsuccess.com/rollup- bundle](http://www.syntaxsuccess.com/rollup-bundle) [http://www.syntaxsuccess.com/webpack- bundle](http://www.syntaxsuccess.com/webpack-bundle) [http://www.syntaxsuccess.com/closure- bundle](http://www.syntaxsuccess.com/closure-bundle)

The uglify code was accidentally commented out in the source on Github, but I have fixed that now.

</comment><comment><USER6> I am really curious about the minimized and gzipped size differences. I created a library a while back[1] and experimented with extreme fileweight (it's an alternative to jQuery with just 3kb minimized + gzipped). I also wrote the topic from what I learned:

[https://medium.com/@fpresencia/understanding-gzip- size-836c7...](https://medium.com/@fpresencia/understanding-gzip- size-836c74b66c0b)

Depending on the code, even if it seems quite large initially it might minimize and gzip quite well. Actually, automatic code generation is the perfect candidate for a good compression. One of the reasons is because this:

        (function(module, __webpack_exports__, __webpack_require__) {})

Will become just:

       (function(a,b,c){})

Which is 5char/function difference with the other example shown in the article with uglify. It becomes negligible when we take into account gzip, since that will be stored only once and then it's just 5char difference overall. So an apparent "module, __webpack_exports__, __webpack_require__" x N becomes just 5bytes of difference in total.

[1] [http://umbrellajs.com/](http://umbrellajs.com/)

<comment><USER3> It's useful to consider not just download size, but also the time required to parse the extra code, and the extra memory used by the code that's parsed and loaded into memory, but not actually used.

 _Probably_ not a concern for desktop/laptop users, but there are plenty of mobile devices out there with relatively slow processors and 1GB of RAM or less.

<comment><USER6> Totally, however that article was mainly about compression file size.

The main problem when we get to optimization is that it highly depends on the browser and version. Parse time is still important, but I'd argue that it's related to both file size and processing power needed, but still less important than both of those.

</comment></comment></comment><comment><USER7> This isn't an apples to apples comparison, as Uglify is disabled for Webpack and Rollup. Of course they are larger without minification.

<comment><AUTHOR> It was accidentally committed commented out for debugging, but the numbers from the experiments use uglify and gzip. Updated the repo as well now.

</comment></comment><comment><USER8> Didn't the Rollup creator claim that Rollup always makes the smallest bundles and if not, it's a wrong Rollup config?

<comment><USER9> Rollup creator here. You're thinking of this tweet[0] which states that correctly configured Rollup bundles are always smaller than _Webpack_ bundles. Closure Compiler on the other hand is currently far more sophisticated than either Rollup or Webpack when it comes to shrinking your code. It's just a little bit harder to use and makes certain assumptions about your code, which is probably why it often doesn't get quite as much attention (though Malte Ubl's splittable[1] provides a nice interface onto CC and supports code splitting — well worth a look).

[0]: [https://twitter.com/Rich_Harris/status/820304090332876800](https://twitter.com/Rich_Harris/status/820304090332876800) [1]: [https://github.com/cramforce/splittable](https://github.com/cramforce/splittable)

<comment><USER8> Ah yes, thanks :)

</comment></comment></comment><comment><USER10> The Closure Compiler with ADVANCED_OPTIMIZATION is a great tool, and I wish more projects used it. However, when I tried it on my own projects I found that it is a relative pain in the arse to export absolutely everything that you don't want the compiler to remove or rename: this might be why it didn't gain a lot of traction.

</comment><comment><USER11> Benchmark like this are not useful if they are not real world. It means you should show minified and gzipped size, the same long signature in webpack will be heavily compressed. Also the TypeScript usage will lead to better optimizations with a TypeScript loader in Webpack.

</comment><comment><USER12> I assume the uglify plugin wasn't commented out when the actual test was run.

I haven't tried this myself, but it's worth noting that you can use closure with webpack: [https://github.com/roman01la/webpack-closure- compiler](https://github.com/roman01la/webpack-closure-compiler)

Hopefully it won't be long before frameworks still depending on html templates are mostly implementing them with es6 tagged template literals, which will make them available for compiler optimizations.

<comment><USER8> I use t7 with (P)React, which works quite nicely :)

<comment><USER12> I hadn't heard of t7 - looks very nice. Similar to [https://github.com/maxogden/yo-yo](https://github.com/maxogden/yo-yo), but I'm impressed with the level of React inter-op and spread support.

I meant more on like Angular implementing it's html templates using template literals and importing them into the runtime, making them inspectable. On second thought, it might be less a matter of the underlying logic and more a matter of when templates are evaluated

</comment></comment></comment><comment><USER13> The closure compiler is a very smart system, and was ahead of it's time in many ways, but now you can get type checking and stronger OO behaviors without being so verbose.

I'm on a team with a moderately large frontend written with the closure compiler, and we are looking forward to using other libraries on new projects.</comment>


Show HN: Grok, a modern wiki for useful, concise, trustworthy content - <AUTHOR> https://grok.how/ <comment><USER2> The email-code-to-login is pretty slow - I've been waiting about five minutes for mine, and am tempted to give up fixing one of the articles.

<comment><AUTHOR> Thanks for letting me know. I'm relying on Mailgun presently. Did you check your spam folder?

<comment><USER2> Yup. Lots of generous offers to purchase sunglasses of dubious origin, but no code.

<comment><AUTHOR> I'd like to get this working for you. Please retry the login, and contact me directly via the contact link at the bottom of [https://grok.how/](https://grok.how/).

</comment></comment></comment></comment><comment><AUTHOR> Your constructive suggestions about Grok are very welcome.

<comment> sahil-kang I'm using Safari on an iPhone X running the latest OS:

        * The main page search bar is really choppy.
          I typed in "lisp" and, when holding down backspace, the cursor skipped around.
        * The website is unwelcoming.
          If this is supposed to be a wiki, then maybe the landing would be better off if it just contained a logo, short description, search bar, and a random-article button.

The idea of a "modern wiki" caught my attention, and I'd be interested to see how this fleshes out.

<comment><AUTHOR> Would you please share more about what makes the site feel unwelcoming to you?

</comment></comment></comment><comment><USER2> Is there a Benevolent Dictator? Is there an editorial policy? Is there a plan in place from this being overrun with flat-earthers, anti-vaxxers and holocaust-deniers? (Or, from some arbitrary point of view: with SJWs, libtards and infidels?)

<comment><AUTHOR> Grok is meant to be, above all things, accurate. Here are the content guidelines --

[https://grok.how/topic-guidelines](https://grok.how/topic-guidelines)

The most impact will come from the community of contributors who are committed to these principles. I'll be supporting them.

It's a big challenge to maximize accuracy while allowing open contribution. We'll need to experiment and iterate on this to improve.

What are your suggestions?

<comment><USER2> I think you need a Benevolent Dictator, or a council thereof, who can delegate as well. Inevitably, you'll have edit-wars, differences of opinion, etc. You need someone to step in and authoritatively declare, "this is what Grok considers to be _truth_ ".

Articles might need a warning before editing to warn users that certain edits or information will be reverted/removed.

<comment><AUTHOR> I think that most disagreements will be resolvable via discussion in topic threads. The Topic Guidelines ([https://grok.how/11](https://grok.how/11)) provide the criteria to judge.

For topics where the truth is a matter of opinion, the topic should probably just describe the different points of view, and qualify their use-cases and pros and cons, rather than arbitrarily picking one.

For the remainder, the side with the strongest references should win. I'll probably need to stratify the community a bit as Grok grows. Those with more influence should judge based on the site principles, similar to the US Supreme Court interpreting the law. I'm cautious to avoid fiefdoms, ulterior motives, and conflicts of interest.

</comment></comment></comment></comment><comment><USER3> Using Google Mail, the signup code email went to my spam folder.

I marked it as not spam.

<comment><AUTHOR> That's helpful to know, thank you. Looks like there's room to improve on email deliverability.</comment></comment>


Physicists Criticize Stephen Wolfram's 'Theory of Everything' - <AUTHOR> https://www.scientificamerican.com/article/physicists-criticize-stephen-wolframs-theory-of-everything/ <comment><USER2> >"I think the popular notion that physicists are all in search of the eureka moment in which they will discover the theory of everything is an unfortunate one," says Katie Mack, a cosmologist at North Carolina State University. "We do want to find better, more complete theories. But the way we go about that is to test and refine our models, look for inconsistencies and incrementally work our way toward better, more complete models."

And yet Einstein did just that in developing General Relativity. Yes, his theory produced made predictions which could be falsified, but GR still represents a paradigm shift, the sort Katie Mack thinks of as "unfortunate".

I am not endorsing Wolfram's work at all. But the idea that science _has_ to progress in a step by step, gradual, collaborative fashion is a naive and historically ignorant view.</comment>